


The Speculative Biology of Elf Horns

by spontaneite



Category: The Dragon Prince (Cartoon)
Genre: Academic, Gen, Illustrated, Meta, Worldbuilding, contains bibliography, resource, speculative biology
Language: English
Status: In-Progress
Published: 2019-03-03
Updated: 2019-03-04
Packaged: 2019-11-08 22:22:26
Rating: General Audiences
Warnings: No Archive Warnings Apply
Chapters: 6
Words: 13,069
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/17989583
Author URL: https://archiveofourown.org/users/spontaneite/pseuds/spontaneite
Summary: Originally posted on tumblr, this is a comprehensive and fairly exhaustive examination of the anatomy, development, genetics, and potential purposes of elf horns, along with a section on useful scenarios for writers. This content includes diagrams and references. There are summaries in each section and subsection.Table of Contents:1.	Introduction2. a) Anatomy of horns....b) Elves with branched horns....c) Sensitivity of horns3. Horn development4. Genetics of horns....a)	Glossary of terms....b)	Hornless elves....c)	Horn placement....d)	Elf type crossbreedingi.	Colour inheritanceii.	Texture inheritanceiii.	Placement inheritanceiv.	Shape inheritance....e)	Elf-human crossbreedingi.	Hybrid geneticsii.	Inheritance of horns5. Possible functions of elf horns6. Scenarios for content creatorsThis work will be updated as I edit/add new sections.





	1. Contents and Introduction

**Author's Note:**

> **Content warnings:** This post contains multiple diagrams detailing the possible internal anatomy of horns. The diagrams are clinical and do not contain gore, but I do mention blood, sinuses, mucous membranes, and other such things in text. In the fiction application section, I also mention scenarios that involve harm to children via damage to their horns. 
> 
> **Warnings specific to section 4:** Considerable discussion of potential genetic deformities relating to horn and sinus inheritance, as well as possibilities of deficits from hypothetical linked genes. In 4e, there is also brief mention of the hypothetical genetics of intersex hybrids.  
> If you are concerned that any of this may be a problem for you, please feel free to contact me to ask for details. 
> 
> This work will be updated as I edit/add new sections. I may take a while to finish putting all of the sections here.

**Table of Contents**

 

1\. Introduction

2\. a) Anatomy of horns

    b) Elves with branched horns

    c) Sensitivity of horns

3\. Horn development

4\. Genetics of horns

    a) Glossary of terms

    b) Hornless elves

    c) Horn placement

    d) Elf type crossbreeding

        i. Colour inheritance

        ii. Texture inheritance

        iii. Shape and size inheritance

        iv. Placement inheritance

    e) Elf-human crossbreeding

        i. Hybrid genetics

        ii. Inheritance of horns

5\. Possible functions of elf horns

6\. Scenarios for content creators

 

* * *

 

 **Reiteration of content warnings** : This post contains multiple diagrams detailing the possible internal anatomy of horns. The diagrams are clinical and do not contain gore, but I do mention blood, sinuses, mucous membranes, and other such things in text. In the fiction application section, I also mention scenarios that involve harm to children via damage to their horns.  
  
**Warnings specific to section 4:** Considerable discussion of potential genetic deformities relating to horn and sinus inheritance, as well as possibilities of deficits from hypothetical linked genes. In 4e, there is also brief mention of the hypothetical genetics of intersex hybrids.

If you are concerned that any of this may be a problem for you, please feel free to contact me to ask for details. 

* * *

 

 

 

  1. **Introduction**



 

Horns are protrusions from the skull of an animal with a core of live bone and an outer sheath of keratin. Keratin is ‘dead’ material, and can also be found in fingernails, hair, and the hooves of some animals. Horns are very distinct from antlers. Horns almost never have branches, for example. Until elves appear whose horns seem distinctly antler-like, I will not be making a detailed analysis of antlers here. Startouch elves probably have horns, not antlers, and will be covered in this post.

n.b. The more technical information about the internal anatomy of horns is almost entirely derived from information on cattle, as due to the fact that we keep them as livestock, there is much more information available about their horns than those of other horned animals. I do, however, offer alternative options for internal horn anatomy of elves.

 

* * *

 

 

 **Summary:** Real-world horns are made out of bone covered in keratin. I am assuming that elf horns work the same way. Horns almost never have branches like antlers do, but they do sometimes, and I’ve got a specific section for explaining how that would work for elves with branching horns. I used a lot of information about cow horns to make this post, because there’s a lot of information available on cows and not so much on antelope or gazelles or such.

 

* * *

 


	2. Anatomy of horns

**Summary for the Chapter:**

> This section contains:  
> a) Anatomy of horns  
> b) Elves with branched horns  
> c) Sensitivity of horns
> 
> Also the vast majority of the diagrams in this work.

**2\. The anatomy of horns**

 

I consider two main possibilities for the internal anatomy of elf horns:

Option 1: Elves have a sinus cavity inside their horns.

Option 2: Elves don’t have a sinus cavity inside their horns.

Option 1 is considerably more complex (and interesting for me as an author) so I’ll be spending more time on it.

Please see **figure 1**. This contains a diagram of an elf who does have sinus cavities in their horns. This skull silhouette was traced from a screenshot of Rayla, so her horns will be our main model today.

 

[ ](https://imgur.com/zspiX4Y)

 

  
I’ll be running through the different parts of the horn labelled here, going from bottom to top.

 **Sinus cavity:** This is where the sinus would extend into the centre of the horn bone. If you were to cut open an elf horn, this part would appear a pale pink colour, and would be full of weirdly shaped hollow spaces with kind of mucous membranes. The sinus cavity develops as the elf ages, and older elves will have hollow spaces extending further along their horns than younger elves. This will be mentioned in more detail in the developmental section.

 **Mucosal sinus lining:** What it says on the tin – this is the mucous lining at the edge of the sinus cavity.

 **Bone core:** This is the section of the horn that is live bone. It is vascularised, meaning it has blood running through it. If the horn breaks, it will bleed. The bone core of the horn is slightly narrower at the base of the horn to allow space for blood vessels to enter it from the head. To my knowledge, this is also where the nerves enter the horn.

 **Bone membrane:** Also what it says on the tin – this is the membrane over the bone core of the horn, separating it from dermis and hypodermis.

N.b. Not labelled here: Hypodermis. This would be the skin layer underneath the dermis, the ‘main’ skin layer, but my main source stated that it is not distinct in horns, tending to ‘be one’ with the bone membrane.

 **Dermis:** The ‘skin’ inside the horn. The dermis in horns nourishes the epidermis, and as such can be expected to contain blood, lymphatic cells, and likely nerves as well. The dermis in horns tends to have a very specialised structure compared to dermis elsewhere in the body, having some really weird villi. Now, I’m not completely sanguine on what exactly villi do in other types of skin, but I understand that in horns, their weird structure forms the basis for the structure of the keratin made by the next skin layer.

 **Epidermis basal layer:**  This is the layer of skin over the dermis. It produces the keratin that forms the hard outer sheath of the horn, pushing it upwards and outwards throughout production.

 **Keratin sheath:** The hard outer portion of the horn, and what will be visible to outside observers. This can be formed in variable patterns and structures depending on the individual and species – for instance, Moonshadow elves seem to have a loosely curved/spiralling texture on their keratin sheaths. Other elves’ horns may be entirely smooth, furrowed, ridged, or even pronged (as in Startouch elves).

 **Oldest part of the horn:** the tip of the horn is the oldest and densest part, and is the first part that grows in a young elf.

 

All that described, let’s talk about sinuses.

Sinuses are a connected system of hollow cavities in our skulls, lined with mucous layers. They’re connected to our respiratory system, and fill with air when we breathe. Most sinuses drain into the nose through small channels. Humans have several sinuses: the frontal, maxillary, sphenoid, and ethmoid. See **figure 2** for _rough_ representation of where these sinuses are located in humans.

 

I should note that, despite being located at various depths in the skull, all of our sinuses are approximately towards the middle of the skull – in other words, along the same sort of mid-line as the nasal cavity. They’re not exactly in the middle, but they’re closer to it than not.

Now, looking at **figure 2** , you might notice that those sinuses are all kind of a long way away from the horns, and their hypothetical sinus cavities. Elf horns do seem to be located quite far back on the skull. As such, if they _do_ have sinuses in them, elves almost certainly have additional sinuses to humans, and quite possibly any sinuses they do share with us will differ in structure.

These additional/differing sinuses could go pretty much any way, but I’ll present one possibility in **figure 3**.

 

 

  
Here, I present an elf with an enlarged and differently-positioned frontal sinus, an intermediate sinus located between the frontal sinus and the horn, and the sinus that extends into the horn cavity. In this case, you might expect the internal skull structure of elves to be slightly different, in order to make room for the extra sinus cavities.

Possible names for the additional horn sinus: parietal sinus, para-frontal sinus.

Possible names for the additional intermediate sinus: prefrontal sinus, para-frontal sinus.

I will be calling the horn-connected sinus the parietal sinus, and the intermediate sinus the prefrontal sinus, as these are probably the most accurate and appropriate names.

 **Note on horn placement:** Not all elf horns are placed on the parietal bone like Moonshadow and Startouch elf horns. Skywing and Sunfire horns, for example, seem to have frontally or pre-frontally placed horns, and there may be evidence for elves with temporally placed horns. The possible morphological differences and implications of this will be discussed in detail in section **4c.**

All this considered, what are sinuses actually for?

_We’re not completely sure._

Sinuses are strange, strange things. One theory is that they’re there to moisten our air, increasing the humidity of air inhaled through the nose. They could hypothetically filter unwanted particles from the air too, or at least some of them. They could, in theory, also help to increase the resonance of our voices. We know that they play a role in the production of mucus, which lubricates and clears out our nasal passages and cavities.

And, last but not least, having hollow spaces in the skull makes it a bit lighter, which is probably especially helpful for elves with large horns who don’t like neck pain. This would probably be my main argument for why I think elves would have horn sinuses, actually. Heads are heavy, and even without horns to make them heavier, our necks can be pretty rubbish at supporting them. Sinuses would, quite literally, lighten the load.

Of course, it’s possible that elves could lack sinus cavities in their horns, per **figure 4**.

 

 

 

  
In this case, you’d still expect the horn to have a lot of the anatomical traits we discussed before, like the bone, the bone membrane, the dermis, the epidermis, and of course the keratin sheath. The only difference would be the lack of sinus cavities. I suppose it’s possible the bone could contain hollow spaces inside it to make itself lighter, such as in many bird bones.

* * *

 

**Summary of Section 2a)**

Some animals with horns have sinuses in them. Some animals don’t. I explained, using diagrams, how the inside of a horn would work for an elf in both cases – sinus and no sinus. Basically, inside the bone of horns, you either have a hollow space for sinuses, or you don’t. Over the bone you have special skin that makes keratin, and over that you have the keratin part of the horn that everyone sees.

Sinuses are hollow spaces in our skulls connected to our breathing system. If elves have sinuses in their horns, they probably have more sinuses than humans, and in different places. This means the insides of their skulls would be slightly differently arranged. I gave an example of a couple additional sinuses elves could have – the parietal sinus, connected to the horns, and the prefrontal sinus, to connect it to the rest of the sinus ‘system’.

I think it would make sense for elves to have sinuses in their horns, since it would help make their horns lighter, which would make elves with large horns less likely to get horrible neck pain.

 

* * *

 

 

**2b) Elves with branched horns**

 

  
We have observed that at least one elf has horns that appear to branch. In our own animal kingdom, there is no animal whose horns contain branched bone. However, there is an animal whose horns have branching keratin: the pronghorn. In The Dragon Prince, we therefore have three basic options for branching elf horn structure. See **figure 5**.

 

 

[ ](https://imgur.com/2KgWZgA)

 

 a) The horn has a bone core that does not branch, but a keratin sheath that does branch. This is similar to the function of the pronghorn’s horn in nature, and is what I’d probably go with personally. This also affords an interesting possibility for elves with branching horns: the pronghorn sheds its keratin sheaths yearly and regrows them.

If elves shed their keratin in this fashion, it might happen yearly, or far more rarely. It would probably represent a time of increased energy needs for the elf – they would likely require more food to supply the regrowth. It’s also possible that if the keratin sheds down to the epidermis, the horn core may be sensitive to the touch until the keratin regrows.  


 b) The horn bones function differently to known examples in the Earth animal kingdom, and do branch. This would mean the bone core extends at least vaguely into every branch of the horn, and has its own dermis and epidermis to grow keratin.  


 c) (Not pictured) These elves don’t have horns, they have antlers. I’ll not go into this in depth, but if these elves have antlers, you can expect them to shed and regrow on a regular cycle. During growth they will be covered in a velvety coating that is somewhat sensitive, and the antler will be full of blood. If cut they will bleed very profusely. When the antler is fully grown, the velvet coat is scratched off, and the antler is hard, smooth, and generally pale to darker brown in colour. It is no longer sensitive, less vascularised, and can be considered ‘dead’. Eventually it will fall off and the cycle will begin again.

 

* * *

 

**Summary of section 2b)**

Elves whose horns branch could work in a few different ways. Either 1, they’re not actually horns at all, but antlers. 2, the bone of their horns doesn’t branch, but the keratin does, and they might even go through a shedding cycle. Or 3, the bone in their horns branches, unlike any animal on Earth.

* * *

 

 

**2c) Sensitivity of horns**

**_Light touch:_** The horns are supplied by nerves. However, they’re also covered in ‘dead’, insensitive keratin, so you can pretty much guarantee they will not be sensitive to fine touch. Light touches, gentle breezes, even stronger breezes – they almost certainly won’t be sensitive to any of that. If a leaf or feather brushes their horn, they aren’t going to feel it.

 ** _Pressure:_** We can expect elves to be aware of pressure or weight on their horns, if only because this will exert pressure and weight on the skull by extension, or change the weight of the horns in a way perceptible to the elf. An elf would notice if you grabbed their horn unless you did it very, very lightly. You could probably get away with a light poke without them noticing. As stated before, they will not be sensitive to fine touches. If the dermis or epidermis under the keratin is sensitive to touch, then a sufficiently tight grab on a horn could _maybe_ be felt through the keratin, but it would need to be a really emphatic grab, and even then I’m not sure it’s likely.

 ** _Pain:_** We can be certain that, if a horn is broken, it will _really hurt._ It’s possible then that a sufficiently hard impact – hitting one’s horn extremely hard on the ceiling, for instance – could cause pain to the inner part of the horn. It would also probably cause pain to the hornbed, the skin around the base of the horn, and possibly the skull. If we assume horn sinuses, it’s also very likely that severe colds or sinus infections could cause ‘horn-ache’.

 ** _Temperature:_** This one is difficult to gauge. Animals with horns are quite difficult to interview about the finer details of what they are sensitive to. What we _do_ know: many horned animals use their horns to play a role in regulating their body temperature. Animals adapted to hot climates can even experience frostbite in the ends of their horns if they’re somewhere very cold. I think it’s possible that extreme cold could cause a sort of ache in the horn. I feel that sensitivity to temperature would only happen if the ambient hot or cold were strong enough to warm/cool the keratin layer and trigger hypothetical receptors on the dermis. This could really go either way.

 ** _Visceral awareness_** _:_ It is very likely that elves would be very aware of the position and size of their horns. This would be due to a combination of the weight of the horns on their head, learned responses, and _possibly_ a vague visceral sensitivity to the nerve-supplied inner horns that allows the elf to feel them there, as with any body part.

We can be sure that elves will have a well-developed awareness of how tall their horns make them, and how much they have to duck to get themselves and their horns beneath obstacles. Elves who get their horns stuck on things a lot are either very scatterbrained and/or clumsy people, have done a lot of growing recently, or any combination thereof.

 ** _Possible exceptions:_** If Startouch elves shed their keratin, then it is possible the layer of keratin-producing epidermis would be sensitive to light touch and temperature until the keratin grows back in. _Possible,_ but not certain.

* * *

 

 

**Summary of section 2c)**

Horns wouldn’t be sensitive to light touches, but they do have nerves running through the bone and skin inside them. If they’re broken, it will be very painful, and will bleed. If an elf hits a horn very hard on something, it could make the inside of the horn hurt. Elves will be aware of pressure or weight on their horns, like if their horns are caught on something or if someone is resting a hand on one. They’ll probably have a strong awareness of how tall their horns make them and where their horns are positioned when they move around. There’s a chance the inside portions of horns could be able to feel the difference between hot and cold.

 

 

* * *

 


	3. Horn Development

**Summary for the Chapter:**

> This chapter concerns the development of horns in baby elves, and how they would change with age. It contains two figures.

**3\. Horn development**

Baby elves, probably to the relief of their mothers, may not be born with horns. The newborn elf might instead have two darker-coloured patches of hairless skin on their skull, where the horns will grow from. Under the skin, the ‘horn bud’ will already be present, and will have been since probably around half way through gestation. It will likely be able to be felt through the skin. Please see **figure 6**.

 

 

[ ](https://imgur.com/aTqt4sY)

 

 

This figure labels the horn bud, the speculative parietal sinus, and the parietal bone the sinus is named for. Not labelled are the speculative prefrontal sinus, the frontal sinus, the ethmoidal sinus, the spheroidal sinus, or the remaining skull bones. This figure is derived from a diagram linked in the sources.

The horn bud is likely to have unusually pronounced nerve growth around it, both prenatally and in infancy, meaning it will be an especially sensitive area on the infant. It’s hard to say what form of sensitivity this would take – could be ticklish, could be soothing. Consider a concept: elf parents stroking their newborn babies’ hornbeds as a common form of affection. Some of this sensitivity around the base of the horn could well remain later into the elf’s life – while it wouldn’t be as sensitive as in an infant, it’s possible that the skin around the bases of elves’ horns could be noticeably more sensitive than the rest of the scalp.

The newborn’s horn buds are essentially tiny, well, buds. Buds of cartilage, bone-producing cells, and keratin-producing cells. They are separate from the skull and not connected to it – yet. The horn will begin growing from birth, and depending on elf newborn growth rate, it may take anywhere from three weeks to several months to protrude a centimetre from the skull. At this stage, it is connected to skin rather than bone on the skull, and is mostly cartilaginous rather than bony. You would be able to poke the horn nub and shift it back and forth a little.

In time, the developing horn produces bone and keratin and fuses to the bone of the skull, and can no longer be wobbled around. We can only guess when this would happen in elf infants. I would estimate somewhere from three to six months, but that’s a very rough guess.

  
In cattle, the sinus cavities begin developing into the horns at around 12 months of age. This would likely occur much, much later in elves. I would think these sinuses might not start fully extending into the elf’s horns until they were at least five years old, possibly even later. The sinus cavities continue to grow in the horns as the elf grows older; an elf fifty years old would likely have a hollow interior almost all the way along their horns. See **figure 7** for a possible progression of the development of the sinus cavities in elf horns.

 

[ ](https://imgur.com/mnlAKRP)

 

 

 

**_Alternatives:_** Some horn-bearing animals _are_ born with horns already present. Elves could be similar, and emerge from the womb with small horns already on their little skulls. These would likely not be any longer than a few centimetres. They may or may not be fused with the skull, but would not have any sinus cavities yet.

 

* * *

 

 

**Summary of section 3)**

I think it’s likely that baby elves are born with the tiniest, tiniest bumps of developing horns under the skin on their skull. If they’re born with any visible horn at all, it won’t be any longer than a couple of centimetres. When elves are born, their horns probably aren’t connected to their skull yet – the horn might fuse to the skull at around 3 months of age. The places where baby elves’ horns grow in are probably very sensitive. Maybe elf parents tend to stroke them. Some of this sensitivity could remain later in life - hypothetically, the skin around the base of the horn could be more sensitive than the rest of the scalp.

If elves have sinuses in their horns, these take a long time to start growing in. The parietal sinus will start growing into the horn maybe at around five years old. An older adult elf will have far more hollow sinus space in their horns than a younger adult or a child. This means older elves will have more hollow horns.

 

* * *

 


	4. Genetics of Horns

**Summary for the Chapter:**

> This is the longest section by far, with five subsections, some of which with subsections of their own. The information is dense, but every section contains a summary.

**4) Genetics of horns**

 

The placement, shape, size, growth, and function of elf horns will all depend on the genetics behind them. As a result, there’s a lot to be said about the possible genetics of elf horns, but as I’m no geneticist, I’ll be going into the scenarios I find most interesting to think about.

 

* * *

 

**4a) Glossary of terms**

Most of these definitions will either be explained or can be inferred from the text. Some probably can’t. Refer to this glossary if you get perplexed.

 

A glossary of terms used in this section:

**Gene** – a part of an organism’s genetic code that codes for a particular physical trait. For example, one gene may decide what shape an animal’s horns grow in.

 **Allele** – a ‘different form’ of a gene. A gene itself may code a specific physical trait, but genes can exist in different forms. For example, the fur of an animal can often come in different colours and patterns, for which differing alleles are responsible. The different forms a gene can take are referred to as alleles. Alleles are inherited – one allele for every gene in an organism is inherited from its parents. Alleles are usually written as upper or lower case letters, such as P or p.

 **Homozygous** – refers to an organism who inherited two copies of the same allele of a gene from each of its parents. Examples of homozygous allele configuration: PP, pp.

 **Heterozygous** – refers to an organism who inherited a different copy of an allele of a gene from each of its parents. Example of heterozygous allele configuration: Pp.

 **Phenotype** – the observable physical appearance of something, generally of a specific body part or trait. For example, a black-furred dog can be said to have a black-furred phenotype.

 **Genotype** – the not necessarily observable state of an organism’s genome. Sometimes you can determine genotype of an organism by breeding it with one or more other organisms and making inferences from the phenotype of the offspring, but otherwise genotype may not be explicitly obvious to the naked eye. The allele examples given for homozygous and heterozygous are also examples of genotypes.

 **Linked genes** – genes that are likely to be inherited together because they’re located close to each other on the same chromosome. Genes are commonly linked when they are essential to related aspects of each other’s function. It can also happen in genes that have very little to do with each other, like the gene for red hair and the gene for freckles.

 **Homeobox genes** – explained in text, but basically these are the genes responsible for making sure things develop in the right basic shape very early in gestation, with limbs in the right places and so on. You may have heard of HOX genes in some sci-fi, which are the homeobox genes relating to limb configuration.

 **Dominance (genetic):** Refers to how alleles on the same gene interact. Dominance is always relative, and an allele that may be dominant over one type of allele could be recessive to another.

 **Dominant allele** – an allele whose associated phenotype will generally be ‘dominant’ over recessive alleles of the same gene. Dominant alleles are represented by upper-case letters, such as P. It usually only takes inheriting one copy of a dominant allele to see it manifesting in the phenotype of the organism.

 **Recessive allele** – an allele whose associated phenotype will generally be overridden by dominant alleles on the same gene. Recessive alleles are generally represented by lowercase letters, such as p. Organisms with one copy of a recessive allele might still have observable phenotypic differences, but frequently, it takes two copies of the recessive in order to manifest completely – in other words, homozygous recessives are more likely to result in phenotypic differences than heterozygous recessives.

 **Incomplete dominance –** when the alleles of a genotype are not entirely dominant or recessive to each other, and the resulting phenotype lies somewhere between the two. For example, if breeding a red snapdragon to a white snapdragon, you end up with pink coloured offspring.

 **Co-dominance** – when, in a heterozygous genotype, you see evidence of both alleles in the phenotype. For example, bi-colour coats in animals, or flowers with more than one colour on the bloom.

* * *

 

 

**4b) Hornless elves**

If elves have genes responsible for making their horns grow, then there is absolutely a chance that you could have naturally-occurring hornless elves. The genetic mechanisms for this and the consequences of it could go a number of ways.

On our own dear Planet Earth, many horned animals have hornless variants, which are referred to as ‘polled’. Because hornless livestock are more convenient to farmers, and because breeding hornless animals is more humane than dehorning, there is a great deal of effort dedicated to intentionally breeding polled livestock.

The genetics of polled animals vary across species, and even within species. In cattle, for instance, the polled allele is dominant, so you can often easily obtain polled variants of a cattle breed simply by breeding a polled bull of one breed to horned cows of another. However, this doesn’t work for all cattle breeds. Genetics of hornlessness can sometimes be more complex than the state of the alleles on a single gene. There is quite a lot of variety in size and shape of cattle horns, so it shouldn’t be surprising that different genes are sometimes involved in hornlessness for some cattle versus others.

In other animals, such as sheep, the polled gene is recessive. In some, such as goats and water buffalo, the polled gene is actually linked to other genes in the body, and hornless animals can have defects in things not related to horns at all, such as their reproductive organs.

I present explanations for both dominant and recessive polled horn genes, but it is important to note: _these are not mutually exclusive._ There could be two different mutations on the horn genes that will inhibit horn development, or different mutations on different horn genes, or multiples of each. It’s completely possible for multiple types of hornlessness to exist in the population at the same time.

 

**If the elven polled gene is dominant:**

The polled allele will be written as P, and the horned allele as p. A homozygous hornless elf is represented by PP, a homozygous horned elf as pp, and a heterozygous elf as Pp.

PP will always result in a hornless elf, and they may not even have horn buds.

Pp will most likely result in a hornless elf, but they may retain horn buds that do not develop. These will never fuse to the skull and will never grow substantially, remaining cartilaginous and malleable for life. These polled horn buds are referred to as ‘scurs’.

pp will result in a horned elf.

 

Whether or not offspring are born with horns depends on the genotype of the parents.

Genetic outcomes:

  1. If PP reproduces with pp, the offspring would be: entirely composed of hornless elves who may have scurs (Pp, Pp, Pp, Pp).
  2. If PP reproduces with Pp, the offspring would be: 50% hornless without scurs, 50% hornless with possible scurs (PP, Pp, PP, Pp).
  3. If Pp reproduces with pp, the offspring would be: 50% hornless with possible scurs, 50% horned (Pp, Pp, pp, pp).
  4. If Pp reproduces with Pp, the offspring would be 25% hornless without scurs, 50% hornless with possible scurs, and 25% horned (PP, Pp, Pp, pp).
  5. If PP reproduces with PP, all offspring will be PP, hornless without scurs. If pp reproduces with pp, all offspring will be horned.



If the polled allele is dominant, you might expect this trait to gain more traction in the elf population, unless the individuals involved made a conscious decision not to have children.

 

**If the elven polled gene is recessive:**

The polled gene will be written as p, and the horned gene as P. A homozygous hornless elf is represented by pp, a homozygous horned elf as PP, and a heterozygous elf as Pp.

PP will always result in a horned elf.

Pp could have variable outcomes. It could result in elves with scurs, elves with smaller stunted horns, or it could have no visible phenotypic effect at all. It’s completely possible that elves with one copy of the polled recessive may be no different on the outside to PP horned elves. I’ll refer to this as ‘undetermined horn phenotype’ in the genetic outcomes.

pp will always result in a hornless elf, likely without scurs.

Genetic outcomes:

  1. If PP reproduces with pp, the offspring would be: entirely composed of ‘carrier’ elves with undetermined horn phenotype (Pp, Pp, Pp, Pp).
  2. If PP reproduces with Pp, the offspring would be: 50% horned, 50% with undetermined horn phenotype. (PP, Pp, PP, Pp).
  3. If Pp reproduces with pp, the offspring would be: 50% with undetermined horn phenotype, 50% hornless (Pp, Pp, pp, pp).
  4. If Pp reproduces with Pp, the offspring would be 25% horned, 50% with undetermined horn phenotype, and 25% hornless (PP, Pp, Pp, pp).
  5. If PP reproduces with PP, all offspring will be PP, horned. If pp reproduces with pp, all offspring will be hornless.



Depending on how carriers of the polled gene manifest, it’s very possible that there could be a lot of elves walking around with no idea that they’re carriers. If they had children with another carrier, they might well end up with a hornless child from the union. You might, alternatively, expect carriers to be aware of the fact that their family line has had hornless individuals in it, and to possibly be wary of having children with an elf with a similar family background.

On the whole, if the elven polled gene is recessive, you can expect to see fewer hornless individuals in the population.

 

* * *

 

 

**Linked genes:**

It’s certain that elves with horn sinuses will have the genes responsible for the sinuses linked to the genes responsible for horns. This will be discussed in more detail in the next section.

It’s possible that, like in some earth animals, the horn genes are also linked to seemingly unrelated aspects of elf physiology. This could be pretty much anything, from skin pigment to reproductive organs to skeletal development. Depending on what genes the horn genes might be linked to, hornless elves could potentially encounter deficits in basically anything. Hornless elves could even have fatal deformities that prevent them from surviving. If canon does not elect to give us any hornless elves, you could use this as one very depressing explanation for why that might be the case.

 

* * *

 

 

**Summary of Hornless Elves:**

Since elves have horns, hornless elves are very likely to exist as a possible mutation on the horn development gene/s. How likely this mutation would be to spread would depend on how dominant the hornless gene is, and also how likely hornless elves are to reproduce.

If the horn genes are linked to other genes, hornless elves could have any number of potential problems. The list of potential problems is as long as the list of functions of the body, so I’m absolutely not going to write it.

 

* * *

 

 

**4c) Horn placement:**

Different types of elves have horns placed at different points on their skulls, and therefore fused to different bones of the skull.

Frontally-fused types: Skywing, Sunfire.

Parietally-fused types: Moonshadow, Startouch.

Temporally-fused types: Hypothetical elf whose skull we see in s1e2*

* _In s1e2, our first scene in Viren’s dark magic workshop shows us what looks like an elf skull on one shelf. The horns of this skull protrude from around where the ears would be, on the temporal bone, and they arch forwards. This skull is not there in later shots of the same scene in s1e3, so it’s unclear whether this should be considered canon or not. It could also potentially be the skull of some sort of horned humanoid animal, such as a horned monkey or ape._

Note, Sunfire horn placement seems almost on the verge between parietal and frontal. I might hesitantly call it prefrontal placement.

Now, the placement of elf horns is most likely determined by what we call homeobox genes. These are a family of similar genes that direct the formation of several basic bodily structures during very early gestation. A homeobox is a sequence of DNA found _within_ genes involved in the patterns of anatomical development in animals (also fungi and plants, but less relevant here). Fun fact: differences in homeobox genes are responsible for the difference in finger and toe counts between humans and elves, as well as the presence of horns versus no horns.

The MSX homeobox genes are the ones responsible for determining the development and structure of the head, face, and teeth. As a result, I would expect elves to have differences in their MSX genes as compared to humans. I would also expect to see differences in these genes between types of elves with differing horn placements. I’m no geneticist, so I’m not going to give examples of additional homeodomains coded for in elves that might be responsible for horns. Instead, I’ll make some reasonably educated assumptions:

  * The MSX homeobox genes tell the foetal elf’s cells where the horn buds should be growing.


  * If elves have horn sinuses, the genes for these will be linked to the genes for horn placement, and their development will also be directed by the MSX homeobox genes.



 

The most interesting thing to consider about the differing position of elf horns is how their sinus structure might also differ – assuming, of course, that elves have sinus cavities in their horns. I see two main options here:

 

  1. Elves all have the same basic sinuses: **frontal, maxillary, ethmoidal, sphenoidal, prefrontal** (see section 2), and **parietal** (see section 2). Depending on horn placement, some of these will develop more dramatically than others. For example, a Moonshadow elf’s parietal sinus will be larger and more developed to extend into their horns, whereas this sinus might be as small as the ethmoidal sinus in a Sunfire elf. _If we assume the existence of elves with temporal-fused horns:_ the number of paranasal sinuses might be one larger, with the addition of the **temporal sinus.** This would be located around the ear, likely slightly above or behind it, but further into the skull. It would drain to the sphenoidal sinus and from there into the nasal cavity.



 

  1. Elves will develop or not develop certain sinuses depending on the horn placement gene the sinus development genes are linked to. For example, a Skywing elf may not develop the parietal sinus at all. This early differentiation would likely take place in the womb, possibly during very early embryonic development.



 

I find both equally compelling, with perhaps a slight preference for option 1. It all depends on what genes are responsible for the positioning and development of both horns and sinuses.

 

With option 1 in mind, I posit the following differences in sinus development between elves:

 **Moonshadow and Startouch elves** : parietal sinus connects to the horns, and is significantly larger than in other elves. Prefrontal sinus may also be larger, to enable better drainage of the parietal sinus into the nasal cavity.

 **Skywing and Sunfire elves** : prefrontal sinus connects to the horns, and is significantly larger than in other elves. Alternatively, it could be the frontal sinus that connects to the horns, but I consider this less likely, as the frontal sinus is much lower on the forehead than the horns, and I would sort of expect these elves to have bulging foreheads if their frontal sinuses were that large.

 **Hypothetical temporal-horned elves:** Given the closeness to the sphenoid bone, I feel that the sphenoidal sinus could connect to these horns. Alternatively, as stated before, these elves might have an additional sinus, the temporal sinus.

 

With option 2 in mind:

 **Moonshadow and Startouch elves:** these elves would be the only ones to develop a parietal sinus in utero.

 **Hypothetical temporal-horned elves:** the hypothetical temporal sinus would develop in these elves only.

 

This might lead to some interesting differences between elf types, as well as interesting implications for hornless elves. Please bear possibilities 1 and 2 in mind as you read the following subsections.

 

* * *

 

 

**Implications for hornless elves:**

This section mainly applies if you consider elves to have horn sinuses.

In the case of options 1, where all elves develop the same sinuses but to varying extents, your hornless elf could end up with a number of different sinus configurations. They’ll have all six/seven paranasal sinuses, but the allele that deactivates horn growth may or may not deactivate the associated sinus growth gene.

As an example: imagine a Moonshadow elf born without horns. The allele that stopped their horns from developing may not affect the linked sinus gene. As a result, their parietal sinus may grow and develop as if the horn was there, leading to cranial deformity later in childhood, as with a dehorned or disbudded elf child. I would consider this most likely to occur if the hornless elf was heterozygous, with only one copy of the polled allele.

If the hornless elf is homozygous, with two copies of the polled gene, I consider it more likely that the parietal sinus either wouldn’t develop beyond its small base state (Option 1 genetics) or wouldn’t develop at all (Option 2 genetics).

Overall, I would assume that polled elves would _not_ experience cranial deformity, simply because polled cattle don’t. Unlike dehorned and disbudded cattle, polled cattle do not present with engorged craniums from sinuses that try to develop but have no room. Unfortunately, there isn’t a lot of literature suggesting why this is – it could be that the calf’s horn-connected sinus is present but doesn’t develop further (most likely), or that the sinus is entirely absent (less likely).

With option 1 in mind, I would expect a homozygous polled elf to have all the usual sinuses, but at sizes indicative of the lack of connected horns. In a heterozygous polled elf, it’s possible that their recessive might be linked to a gene that allows the associated sinus to grow, leading to cranial deformity.

 

* * *

 

 

**Summary of Horn placement**

Different types of elves have horns growing from different points on their heads. The genes most likely responsible for determining this are called homeobox genes. These horn placement genes would be linked to the sinus genes, meaning that it would be fully possible for elves with horns in different locations to still develop sinus cavities in their horns.

Genetically-hornless elves could potentially encounter problems if their sinus genes are not also suppressed by their hornless genes.

 

* * *

 

 

 

**4.d) Elf type crossbreeding**

 

If different types of elf interbreed, this could have a large number of outcomes for their horns.

Different types of elves have very different horns. They seem to vary in colour, texture, shape, and positioning depending on type, which means that inheritance of these traits could differ in hybrids.

 

**i. Colour:**

Horn pigment would probably be influenced by the keratinocytes (keratin-producing cells) found in the dermis and epidermis of the horn. Most horns in Earth animals tend to be black, grey, brown, or reddish-brown. There is really not a lot of information to be found about the genes determining pigment in animal horns. However, there’s a great deal about the pigment genetics of a different type of keratin: human hair. In human hair, pigment is largely determined by the amount of different types of melanin in it. I feel that elf horns could easily work the same way.

The horn colour inheritance would depend on how the horn colour alleles interact. Some horn colours may be dominant or recessive to others, even within the same elf type. For example, brown horns may be dominant to red horns in Sunfire elves. It’s impossible to predict how allele dominance might work out in cross-type hybrids, so you could make this go either way.

If the genes responsible for horn colour are incompletely dominant, then it’s possible that your hybrids may present with colours that are somewhere between those of their parents. For example, a Sunfire-Skywing hybrid with dusty red horns.

If the genes responsible for horn colour are co-dominant, you could even end up with horns that have patchy or variable colour – bicolour horns are a real possibility. This would be more likely to take the form of random patches of one colour than any sort of pretty gradient, though.

 **Summary:** Depending on how the colour genes work and interact, elf crossbreeds could inherit a colour from one parent, a mixture of the colour of both parents, or even a patchwork combination of the two.

 

 

**ii. Texture:**

Horn texture would be influenced by the villi structure of the dermis and epidermis within the horn, as these produce the keratin, and the structure of their villi determines the appearance of the keratin. Moonshadow elves seem to produce keratin with length-ways ridges in loose curving shapes. Sunfire and Skywing elves seem to have smoother horns. This will be due to differing structure of the villi in the horn skin.

Much as with colour, we can consider dominant/recessive, partial dominance, and co-dominance to decide how texture is inherited.

Keratin texture may be determined by alleles on the same gene that are dominant or recessive to each other. In this case, hybrid offspring will inherit one parent’s texture or the other’s.

If the alleles are incompletely/partially dominant, you might end up with a texture somewhere between the parents’. Please note that this might not be structurally stable for the horn: horns with mixed textures may break more easily, chip or scratch more easily, or have more points of weakness.

If the alleles are co-dominant, you could end up with some crazy mix of the two. Please note that this might not be structurally stable for the horn: horns with mixed textures may break more easily, chip or scratch more easily, or have more points of weakness, especially in areas where one texture lies alongside another.

Depending on how the genes are represented, and if there are multiple genes involved, crossbreeds could be born with entirely new horn textures that may or may not be structurally stable.

 **Summary:** depending on how the texture genes work and interact, elf crossbreeds could inherit a keratin texture from one parent, a mixture of the textures of both parents, or even a patchwork combination of the two. The last two options could be problematic for the offspring – it’s possible that some combinations wouldn’t be well-designed, and could lead to the horn keratin breaking or being damaged more easily.

 

 

**iii. Shape and size:**

 

Different types of elves have different horn shapes and sizes. Some, like Startouch elves, have entirely different structural configuration, what with their prongs. This would be determined by the MSX homeobox genes. As such, inheritance of horn shape is a bit trickier to work out, as it depends heavily on how horn shape is represented in the homeobox genes, and whether these genes are consistent among elves, and also how many genes are involved with it.

For this I can really only throw possibilities your way and let you choose, because I’ve no clue which is most likely.

  * Hybrid offspring could inherit the shape/size of one parent or the other with no changes or alterations.



 

  * Hybrid offspring could inherit a shape/size somewhere in between – for example, a Sunfire-Moonshadow hybrid with horns pointing back-and-up, curved or straight. This would have a chance of deformity, with poor combinations of traits leading to horns that don’t grow correctly, are stunted, or anything along those lines.
  * Hybrid offspring could present with a shape/size wholly different to either parent due to strange interaction of genes. This could be cool and interesting, or it could be a huge problem. This is where deformities could potentially occur. Weird interaction of size-related genes, for example, could lead to offspring with horns that are far, far too large, probably leading to significant neck problems and possibly over-developed sinuses. Problems with horn shape inheritance could also lead to deformities within the structure of the horn itself – the bone might not develop properly, or be properly vascularised, and so on.



Hybrids of Startouch elves and others might encounter a unique factor here: whether or not the offspring has branched horns, they’d have a chance of shedding their keratin periodically.

 **Summary:** Outcomes for the shape and size of hybrid horns are very, very heavily dependent on information I don’t have about how elf horn genes are represented. So the possibilities are: hybrids could inherit shape and/or size from one parent only. They could inherit a combination of the shape and/or size of their parents’ horns, which may not be well-formed and healthy. Or they could end up with dramatically differently shaped and sized horns, which could be cool and awesome-looking, but would have a much higher chance of horrible deformity.

 

 

**iv. Placement:**

 

As discussed at length in **4c)** , horn placement depends on the MSX homeobox genes. This is the most likely point at which you’ll see deformities or problems with hybrid offspring, as it relies on linked genes being inherited properly.

I think the main possibilities here are as follows:

  1. Horn position is inherited wholesale from one parent or the other, along with the linked genes for sinus development.
  2. Horn position of hybrids can be somewhere between that of the parents.



2 is where we see potentially very large problems for the offspring.

While the sinuses and their development might be very neat and tidy for the ‘pure’ subtypes of elf, there’s no guarantee that this would hold true if they produced offspring with abnormal horn placement. If a Moonshadow-Skywing hybrid is born with horns somewhere between the parietal and frontal bones, which sinus will connect to it? Will the parietal sinus attempt, unsuccessfully, to grow into a horn that isn’t in the right place? Will the prefrontal sinus attempt to grow into the horn, and successfully pneumatise it? Will both prefrontal and parietal sinuses grow to full horn-penetrating size? Will the sinuses be placed differently, to allow optimal growth into the horn?

Again, the concept of horn sinuses provides a potential point of contention for hybrids. If the sinuses don’t form in a way capable of connecting to a poorly-positioned horn, you could end up with bulging craniums, or hollow horns disconnected from the respiratory system, or any derivation therein.

All told, I feel it would be much better for the health of inter-type hybrids if 1 is the possibility that holds true here. As such, I’m going to call this the likelier option, because I don’t think it would make sense for different elf types to have difficulty interbreeding.

 **Summary:** if you love your hypothetical elf subtype hybrids, please assume that they will inherit the horn placement of either one parent or the other. If the horns end up being located somewhere between, I can only imagine what problems that could cause for them. And I did imagine. Extensively. I even wrote it down.

 

* * *

 

 

 **4e) Elf-human hybrids** :

 

* * *

 

 

**i. Hybrid genetics**

 

Note: this section assumes that humans are native to TDP world, and were not transplanted there thousands of years ago by weird dimensional shenanigans. It also assumes that humans and elves are closely genetically related enough to interbreed, an assumption which has its own implications.

 

Now, this post is about horns, so I really didn’t intend to go into hybrid genetics more than I had to. But that ship has well and truly sailed, so…here I go talking about hybrid genetics, specifically as they apply to hypothetical elf-human hybrids.

To begin with, if elves and humans are capable of cross-breeding, this means they must have a fairly ‘recent’ common ancestor, and elves and humans would _probably_ be part of the same taxonomic genus. There are known examples of hybrids occurring between different genera, and very rare examples of hybrids between different families, but you can absolutely guarantee that anything further removed than interspecific (hybrids between two species of the same genus) would be infertile.

In this case, the early ancestors of both elves and humans would be different from the early ancestors of real-world humans. This means that humans may be physiologically different in TDP than in the real world. Honestly though, I would just hypothesise that members of the _homo_ genus and their ancestors in this universe had horns, up until whenever humans or humans’ ancestors split off from the horned members of the genus. This seems likely enough, given there are examples of what seem to be horned possibly-mammals in TDP’s opening Which leads me to the point:

Given that real-world humans did interbreed with other members of the _homo_ genus around 47k years ago, I consider it very possible that all humans have a low percentage of elf DNA, and elves a low percentage of human DNA. In our world, we have about 1-4% of non- _homo sapiens_ DNA, but the other members of the _homo_ genus died out a long time ago. In TDP, therefore, there could be a much higher proportion of mixed DNA around, though of course that will have lessened in the last thousand years. Given their relative lifespans, elves in current events probably have more human in them than humans have elf. Ironic, really.

If modern elves and modern humans have the same number of chromosomes, and are part of the same genus, they might be able to have fertile offspring. If they have different numbers of chromosomes, there’s basically no chance their offspring will be fertile. If there is any chance at all, it’ll be for female hybrids only, who may be able to breed with a male human or elf (but possibly only one of the two, rather than either species). As a general rule: female hybrids will be much, much more likely to be fertile than male hybrids, due to the sensitivity of the sex-determining genes on the Y chromosome. Hybrids with XY chromosomes may be more likely to be intersex or have hermaphroditic traits than females, and will almost never be fertile. For more information on this, refer to ‘Haldane’s Rule’, linked in the references.

Historically speaking, if there ever was crossbreeding between ancient elves and humans, this would be how elf genes entered the human genepool and vice versa: female hybrid offspring would breed back to a male of one of her parent species, produce fertile offspring, who would then breed with more members of the species of their father, and so on.

You would, on the whole, have two categories of hybrids: male elf + female human (elman?), and male human + female elf (helf? Humelf? I’ll go with ‘helf’, as it’s funnier).

An elman would have the mitochondrial DNA of a human, and a helf would have the mitochondrial DNA of an elf, as mitochondrial DNA is 100% matrilineal.

* * *

 

**Summary of Hybrid genetics:**

In TDP, humans and elves are almost certainly members of the same genus, which means they’ll be closely genetically similar. Quite possibly close enough to interbreed and produce fertile offspring. In the case of elf-human hybrids, your hybrid females will probably be the fertile ones. Male first-generation hybrids may be infertile, or intersex, but will be unlikely to be able to breed.

Now, finally, onto actual horn inheritance:

* * *

 

 

**ii. Horn inheritance**

 

Given that humans and elves share common ancestors, humans could be considered hornless elves more than elves could be considered horned humans. As such, humans could be considered polled for the purposes of thinking about hybrid genetics; in other words, some ancient humans would have been born hornless, most likely with this as a dominant gene, and horns would eventually have been bred out of the population. Depending on how long ago this was, it could be possible for humans to very, very rarely be born with naturally-occurring horns, which I imagine wouldn’t go terribly well for them or their parents in the modern political climate.

This does make things simpler for elf-human hybrids, however. Given the shared genetic heritage, there might well be room in the human MSX homeobox genes for horn-related genes. If the genes are similar enough, it could just be a matter of the polled allele encountering the horned allele: the human could be considered PP, the elf pp, and their offspring would be Pp, Pp, Pp, and Pp. In this case, you might expect all hybrid offspring to be hornless with scurs. Hybrid female offspring, Pp, would then be able to breed back to a male elf and produce offspring with horns, pp.

I consider it extremely unlikely that the human polled gene would be recessive, as otherwise humans with horns would be relatively common, or at least not unheard of. The only way horns wouldn’t be prevalent in the genepool is if something happened in antiquity to wipe out all or most individuals with the dominant horn allele.

Now, because you and I both probably enjoy the idea of horned hybrids, I’ll put forwards some other possibilities.

  * The human polled gene has differentiated enough from the elf horn gene that when the alleles meet, you encounter principles of **incomplete dominance.** This would mean that when you end up with a Pp heterozygous hybrid, neither the P or p allele would be fully dominant, and the phenotype would manifest somewhere between the two. So in this case, your elf hybrid would probably have small, stunted horns, or at the very least shorter horns than their elf parent.
  * If the human polled gene and the elf horned gene are **co-dominant** , this means that signs of both alleles would manifest in the hybrid offspring, which could end up being extremely messy. This is probably the possibility most likely to result in deformity, but it could also have exciting possibilities such as hybrids with a single horn. But, on the other hand, it could result in horrifying deformity. Examples: some parts of the horn genes functioning and others decidedly not functioning. There’s a lot of ways this could go and many of them are highly unpleasant, especially when we think about linked sinus genes.



All things considered, you don’t want your horn alleles to be co-dominant in hybrids unless you’re interested in creating a story where this is one of the reasons elf/human relationships might be forbidden: the children often have a very bad time, genetically speaking.

If you want cute healthy hybrid kids, please assume either dominant polled allele for hornless kids, or incomplete dominance for horned kids.

Everything horn-related that the hybrid _does_ inherit will be from their elf parent: shape, texture, colour, and so on. Unless – and this is a really small possibility – enough of the human colour/shape/texture-determining genes linger from antiquity in the genome, in which case the offspring could have cute stunted horns in colours and shapes and textures not seen for tens of thousands of years.

 

**On sinuses:**

Depending on genetic heritage, humans in this setting might well have extra paranasal sinuses themselves. If they don’t, then inheritance of horn-related sinuses would likely be linked with inheritance of horns in general, as these genes are strongly linked. I consider it quite likely that TDP humans would have the extra sinuses, even if only as small vestigial cavities.

On the whole, though, I consider sinuses one of the greatest potential points of deformity in these hybrids. If you have a Moonshadow-human hybrid, for example, everything could align nicely and the incomplete dominance could give you a child with small horns, functional parietal sinuses, and functional miscellaneous paranasal sinuses. But…on the other hand…

On the other hand, it could go wrong. It could go wrong in many ways. The parietal sinuses might develop properly, but the prefrontal might not, leading to partial or complete isolation of the parietal sinus from the respiratory system. The drainage channels between all the sinuses could be malformed, leading to a child who is very likely to experience frequent sinus infections. The homeobox genes for the sinuses could get mixed up, and cause all potential horn-sinuses to develop to full size, leading to very dramatic cranial deformity as the child ages.

If I wanted to create a hybrid child character who was mostly healthy, had horns, but did suffer some health problems, I would probably choose the drainage option. Then you’d have a kid who got sick quite a lot, which would be great for angst, but wouldn’t have as much risk of outright mortality or horrifying miscellaneous problems.

 

* * *

 

 

**Summary of Horn inheritance**

For the purposes of talking about hybrids, humans can be considered to have the ‘hornless’ gene rather than no horn gene at all. This means that a human breeding with an elf could work in the same way as a hornless elf breeding with a horned elf – at least, as far as the horns are concerned. Hybrids would either be born hornless with non-developing horn buds, or with small stunted horns that would likely be the same colour, texture, shape, and placement as their elf parent’s.

Sinus layout would also likely be inherited from the elf parent. If it wasn’t, or if not all of the linked genes came through properly, this could lead to serious problems for the hybrid.

* * *

 


	5. Potential Functions of Elf Horns

**Summary for the Chapter:**

> This section will propose and evaluate potential purposes for elves' horns. This is one of the least dense and most readable sections.

**5\. Potential functions of elf horns**

 

This section will propose and evaluate potential purposes for elves’ horns.

Please note: this section heavily assumes that elves have some sort of evolutionary history, and that they did not spring fully-formed from their primal sources however many thousands of years ago. Each subsection will contain references first to ‘early’ elves, who would be the primitive ancestors of elves, and then to modern elves.

* * *

 

**a) Fighting, rivalry, and inter-elf disputes**

This is the least likely of all options. While many horned animals use their horns to fight each other for territory, mates, or just because they took a disliking to each other, this would not be feasible for elves.

All horned animals on Earth are quadrupeds, which already puts them in a more viable position to use their horns as weapons, as they don’t need to bend forwards as far to headbutt something with their horns, or lock horns with each other. An elf, comparatively, would need to bend over into a downright silly position to get their horns to bear on an opponent. This would be easier for hypothetical elves with forwards-pointed or curved horns, but they would still encounter other issues.

Horned animals tend to have more powerfully built and supported necks than elves. Elves seem to have similar neck arrangement to humans, and as such we can assume they’re not made to withstand significant force applied to the head any more than we are. Even if an elf tried to use their horns to whack someone else, the combination of the position they would need to be in, and the force of impact, would probably cause very serious damage to their necks over time.

It is technically possible that very, very early ancestors of elves were quadrupedal, and had better structural arrangement for using horns as weapons. The process of evolution from a quadruped to an elf would be long enough though that the horns probably ( _probably,_ not certainly) would have been selected out of the genepool once they stopped being useful for fighting, unless they had some other useful purpose. Like one of the others yet to be mentioned in this section.

_Implications for modern elves:_ Whether or not horns evolved as weapons, if horns are viewed as weapons, a posture with the head bending forwards towards someone could be seen as aggressive or confrontational. Lowered or brandished horns could be elf-specific body language cues.

* * *

 

**b) Self-defence against predators**

This is still fairly unlikely, but not as much so as **a)**. Elf horns, especially backwards-pointing ones, could hypothetically be a deterrent against predators with a tendency to ambush or attack from behind. It would make the back of the neck a less tempting target, as there would be pointy things near there that could poke your eyes out if you tried to go for it.

If elf horns do serve a defensive purpose, it would probably be more as a passive deterrent against neck attacks than as weapons the elf could use. If, for instance, an elf were attacked from behind, they probably could jerk their heads backward to gore the attacker, but they likely wouldn’t be able to do it with much force due to limited neck strength, so the defensive damage they could cause would probably be quite superficial. They might also damage their own necks in the process.

_Implications for modern elves:_ If horns do serve a defensive purpose, an elf might have a reflex when being attacked/startled from behind to jerk their heads backwards to hit the assailant with their horns.

* * *

 

**c)** **Some sort of magical purpose**

There is basically nothing concrete in canon that would indicate this, but nothing that would directly refute it either. Horns could, in theory, somehow facilitate an elf’s connection to their primal, perhaps as a repository of their arcanum. I’m a bit sceptical of this possibility, but I’m including it just in case.

_Implications for modern elves:_ Elves who break their horns may be unable to cast magic as well or at all, if they were a mage. If horns have a fundamental connection to the arcanum, it’s possible that an elf with broken horns might not be able to access innate abilities, such as a Moonshadow elf’s Moonshadow form. If this is the case, there might well be considerable fear and even stigma surrounding the idea of horn loss.

* * *

 

**d)** **Thermoregulation**

This one is fairly likely. As previously mentioned, many horned animals on Earth use their horns as one way to help them control their body temperature. Horns contain live bone, which means they contain blood vessels. Assuming these blood vessels are capable of the same things most blood vessels are, this means they can dilate (get wider; vasodilation) or contract (get thinner; vasoconstriction).

These are functions used by the body to control how much heat is lost through the blood. If the blood vessels are dilated, more blood is running through them at once, meaning that there’s more blood at the surface to lose heat from. Vasodilation is used to lose heat when the ambient temperature is too hot. The opposite is done when the ambient temperature is too cold – the blood vessels contract so that they’ll lose less heat from the blood.

This would make horns more useful for heat loss than heat retention, as the presence of horns always provides more surface area to lose heat from than the absence of horns.

The likeliness of this depends heavily on where elves originate from. It is entirely likely that different kinds of elf would differ in the thermoregulatory tendency of their horns. We would see certain physical differences between types of elf if this is the case:

Elves who need to lose heat through their horns would have thinner keratin sheaths on their horns. Elves who need to keep heat as much as possible would have thicker keratin sheaths on their horns.

My personal candidate for ‘most likely to use horns for thermoregulation’ is Sunfire elves. There’s two possibilities for them: that their Sunfire abilities make them need ways to lose heat to stabilise body temperature, or that they’re not in danger from high temperatures and instead are very vulnerable to cold. Technically they could also not suffer from high temperatures and also not be vulnerable to cold, but in the context of thermoregulation, the first two are most important when talking about horns.

Sunfire elves vulnerable to cold would have thick keratin in their horns. Sunfire elves vulnerable to overheating would have thin keratin. I personally think the former is much more likely, because the amount of heat they’re seen channelling is more than could be offset by a pair of heat-sink horns.

_Implications for modern elves:_ Elves adapted to hot regions and to losing heat through their horns would be more vulnerable to cold. Their horns will lose heat for them whether they want it or not. If they end up somewhere cold enough, they can even experience frostbite in their horns. If they end up somewhere _really_ cold, they could also probably experience horn frostbite whether or not they’re hot-climate adapted.

* * *

 

**e) Sinuses**

If we assume the ‘elves have horn sinuses’ theory, then the extra sinus space afforded by their horns could be very important to their biology. We may not be completely certain what all sinuses are actually for, but bodies in general seem pretty adamant that they’re important and need to exist. Things sinuses could do in elves: produce snot, make their voices more whoa, help them filter out nasty stuff from the air they breathe, and make their horns less horribly heavy.

If elves have horn sinuses, this means their horns fill with air when they breathe. That’s pretty cool.

_Implications for modern elves:_ Mainly apply if an elf loses a horn or has them removed at a young age, or gets a sinus infection. This will be covered in more detail in section 5) Scenarios for content creators.

* * *

 

**f) Mate selection**

This is probably the likeliest purpose for elf horns of them all: that their horns developed at least in part as a characteristic that influenced how primitive elves selected their mates. From this perspective, the horns of an elf could be called a _secondary sexual characteristic_ , which means that they would be part of how ancient elves chose mates, but not directly part of elf reproductive function _._ In elves, horns of a certain size might signal that their bearer is old enough to be searching for a mate. They would also have been an indicator of how fit and healthy the elf had been over their lifetime, as malnutrition during development can affect the shape, size, and texture of horns.

In nature, animals with horns tend to select mates with larger horns. This would partially be because of the defensive capacity of animals with horns, which doesn’t apply as much to elves. However, as larger horns represent a greater energy expenditure to grow and maintain, they indicate that the potential mate may be healthier and stronger than rivals. This would be especially true for any elves who might shed any portion of their horn, such as hypothetical antlered elves, or the hypothetical pronged keratin of Startouch elves.

Being part of mate selection would explain why elves have horns even if they don’t serve any other useful function. For instance, if elf horns are useless for self-defence, don’t have sinuses, don’t thermoregulate, and don’t play a role in magic, there would be no point in having them. Growing horns would be expensive in energy, using up limited biological resources that could be spent growing or maintaining other parts of the body instead. But nature shows us again and again that many animals will grow very energy-expensive body features, such as a peacock his tail, if it might attract a mate.

If there isn’t any other obvious, very useful reason for elves to have horns, the only remaining possibility is that they contributed to mate selection.

 

_Implications for modern elves:_ We can expect elves to be conscious of the appearance of their horns much as many humans are conscious of the appearance of their hair. We can expect elves to consider certain horn-related characteristics attractive in other elves. They may have preferences for certain horn shapes, as humans may have preferences for certain hair or eye colours.

We can expect elves to visually enhance their horns and make them more noticeable, such as by decorating or ornamenting them – which, I must point out, is indeed what elves seem to do in canon.

Elves may also easily notice things about each others’ horns that indicate poor health, much as we would notice someone looking sick and pale.

 

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**Summary of section 4)**

Elves probably don’t consider horns to be weapons for fighting or self-defence. If they tried to use them to fight, they would probably damage their necks. It’s still possible that certain ways of holding one’s head and horns could be elf-specific body language, though – like lowered horns meaning anger or aggression. It’s possible that elf horns might be involved in their magic, but we’ve seen no sign of it in canon yet.

Elf horns could be used to help regulate body temperature – if this is true, some elves will be more sensitive to cold, because their horns are designed to lose body heat. They might even get frostbite in the ends of their horns. If elves have sinuses in their horns, their horns would play a role in maintaining their breathing system, and would be lighter than you’d expect big head-mounted horns to be.

If elf horns aren’t useful for any of these things, or even if they are, the most likely possibility for why elves have horns: early elves selected mates based on what their horns looked like. This would mean that modern elves probably consider horns something they can be attracted to in other elves, like nice hair or hands or eye colour. Elves will probably want to make sure their horns look nice and are presentable. This seems very likely, since canonically, elves do decorate their horns, drawing attention to them and making them look more interesting.

 

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	6. Scenarios for content creators

**Summary for the Chapter:**

> Contains basic overviews of some scenarios that might be useful for authors or other content creators.
> 
> Currently includes:  
> Horn breaking, horn removal, congenital hornlessness, sickness, fluff, shedding, malnutrition, growing pains, cross-type elf hybrids, and elf-human hybrids.

**6\. Scenarios for content creators**

 

This section is directed at people who produce content involving elves, or horned half-elves. This could be writing, producing OCs, or anything of the sort. This section will involve a fair bit of discussion of horn breakage, as well as intentional horn removal in adults and children.

 

**_Horn breaking_ **

If the very tip of a horn is broken off, it may not bleed. It will probably not grow back.

If a horn is broken further down the horn, it will be very painful, and will definitely bleed. There is a _chance_ that it may grow back. Someone who has recently suffered a broken horn will probably want to stop it from bleeding, try to prevent infection, and use some variety of painkiller.

If your elves have horn sinuses, infection may be likelier when the horn is broken, and could spread to the respiratory system quite easily. It could also interfere with the natural function of the sinuses.

Side note on breaking sinus-bearing horns: since the air the elf breathes will flow in and out of their sinuses, if your elf has really bad breath and breaks a horn, you’ll be able to smell it in the horn.

 

**_Horn removal_ **

Removing an adult elf’s horns, or the horns of a child, would be an incredibly painful and traumatic procedure. It could take them a long time to recover, and they could have difficulty adapting afterwards, possibly having issues with getting used to the lack of weight on their heads. To remove established horns, you would need to break or saw them off, which would cause significant pain and bleeding.

Removing the horns of a baby is still painful, but easier. If you have a child young enough that their horn buds haven’t fused to their skull yet, the procedure is known as ‘disbudding’, and the horn bud can be removed to stop the horns from growing at all. As the hornbeds of infants are very sensitive, this will cause them pain for days if they aren’t provided with medication, though the wound itself will heal quite quickly. There are several methods for disbudding, used on cattle, that can be researched by any content creators who care to. If you’re writing about a baby half-elf whose parent wants to hide their elven heritage, you might choose to have them disbudded. Removing the skin at the top of the horn bud can also prevent horns from growing.

Important note: if your elves have horn sinuses, _removing the horns of a young child will cause developmental issues._ If those sinuses would naturally grow into the horns, that means they _need_ to be there. In the absence of horns to grow the sinus cavity into, the parietal sinus will make room in the skull itself, leading to a bulging cranium. An elf child who grows up without horns will have a visibly misshapen skull. As this has only been observed in dehorned/disbudded cattle, it’s unknown what effects this could have on the cognition of a sapient being like an elf. It could have a whole host of neurodevelopmental effects.

 

**_Congenital Hornlessness_ **

It is entirely possible that an elf could be born without horns, due to a mutation in one or more of the genes related to their horn development. Depending on whether the mutated gene is dominant or recessive to the usual gene, they could have a higher or lower chance of passing this to their children.

 

**_Sickness_ **

If your elves have horn sinuses, then severe colds, flu, or sinus infections will probably give your elf horn ache. This could be handy for anyone who likes to write sickfics, as it’s a new and exciting way you can cause them misery.

Elves with larger horns, and elves older than the age of 5, will be able to feel sinus infections very unpleasantly in their horns.

Elves are probably more likely to experience sinus infections than humans.

Cross-type elf hybrids are likely to have a slightly higher chance of chronic sinusitis, and elf-human hybrids even more so.

 

**Fluff**

If you enjoy writing fluff: the skin around the base of horns is likely to be more sensitive than the rest of the scalp. This will be especially true for babies whose horns haven’t grown in yet properly, but some of the sensitivity could easily linger into adulthood. So, scalp massages for elves would be extra great around the horns, probably. Would also probably be a great way to help kids calm down and get to sleep.

 

**_Shedding_ **

If your elf has antlers or is a Startouch elf with keratin prongs, they will shed their keratin from time to time. How often this might happen is up to you. In pronghorns it happens yearly, but you could easily synchronise your elf’s shed with some variety of cycle inherent to their primal source, or something else. They will probably be hungry when they are regrowing their keratin. It may or may not itch. While the dermis is exposed, it may or may not be sensitive to light touch.

 

**_Malnutrition_ **

An elf who wasn’t eating well or who was sick a lot when their horns were growing might show signs of it on their horns. Inconsistent diet or high energy needs can make energy divert from growing the horn, which can lead to ‘ridges’ in the keratin where it’s thinner or a different texture to usual. If an elf had been sick or starving a lot as a child, another elf would probably be able to tell by looking at the shape or surface of their horns.

 

**_Growing Pains_ **

Growing pains are sometimes reported by children who are doing a whole lot of growing. It’s usually described as an ache, and usually only occurs in limbs, especially legs. There isn’t a great deal of concrete evidence on how growing pains might work, but it seems to be more common in active children.

It’s my personal opinion that elves probably would not have any sort of growing pain in their horns. This is for a few reasons. Firstly, elf horns probably grow really slowly as they age. Secondly, existing evidence on growing pains seems to favour it being more related to muscles and joints than the bones of the limbs themselves, so it seems very unlikely to occur in horns. But if you like the idea, feel free! Go ahead. Also: developing sinuses might hypothetically feel sore or prickle, which would start at about age 5.

 

**_Cross-type Elf Hybrids_ **

When different types of elf have children together, the horn-related traits they inherit could vary. Depending on how the genetics work, they could inherit horn position from either parent. Horn colour and texture could be inherited from one or the other, or as a mix of the two, or even as a funky patchwork of the two. Shape could be a one-or-the-other thing, with a smaller chance of an in-between shape or an entirely new shape. Size would likely be somewhere between, but related to shape. More information on this back in 4d).

 

**_Elf-human Hybrids_ **

If elves and humans are capable of producing offspring together, humans can basically be considered to have had horns in their evolutionary history, which means there’s a couple possibilities for how the horns of hybrid children would come out. Either they’d be born with horn buds that don’t develop, or small stunted versions of their elf parent’s horns. Also, first generation elf-human hybrids probably wouldn’t be fertile unless they were female. More information on this back in 4e).

 

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**Author's Note:**

> It may take me a while to add all of the sections to ao3, as I'll need to edit a whole lot of formatting, and I don't enjoy that. If you get impatient, the link to the currently mostly up to date tumblr post is as follows:
> 
> https://tenspontaneite.tumblr.com/post/183196023016/meta-post-elf-horns
> 
> Pre-emptive advertising: I intend to write a fanfiction for this fandom. In fact, I have already written about 11k of the thing. Perhaps keep an eye out for it?


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